Immunogenicity and reactogenicity of two recombinant hepatitis B vaccines in healthy adolescents on two-dose schedule

This is an open, randomized study to compare the immunogenicity and reactogenicity of two recombinant hepatitis B virus (HBV) vaccines. The HBV-NF is a new formulation with a new adjuvant phenoxyethanol which replaced the conventional adjuvant of a commercially available recombinant HBV vaccine (Engerix-B). These two vaccines had the same 20 micrograms hepatitis B surface antigen (HBsAg). They were administered to the deltoid muscle of 116 healthy adolescents, aged between twelve and eighteen years, according to the 0, 6-month schedule. Serum was taken at month 0, 1, 6, and 7. Antibody to HBsAg was tested by radioimmunoassay. Geometric mean titers of both vaccines displayed no significant difference at month 1, 6, and 7. Following the second dose of vaccine, the seroprotection titer (10 mIU/ml) rates at month 7 were 90.9% in HBV-NF and 93.4% in Engerix-B, respectively (p = 0.43). The incidences of local and general adverse reactions were from 3% to 7% without significant difference between the two vaccines and the reactions were all mild and tolerable. Based on this study, regimens of this two-dose schedule proved to be safe and immunogenic, which may provide a cost-effective alternative for HBV mass vaccination program in adolescents.